Bond head assembly, bonding machine and bonding method

Abstract

The present invention aims to provide a bond head assembly, a bonding machine and a bonding method. The bond head assembly comprises a fixing holder, a first driving unit, a bond head frame, a second driving unit, a capillary, a third driving unit, a cutting tool, a first measurement assembly and a second measurement assembly. The third driving unit is a solenoid; a limiting portion is provided on the bond head frame; when actuated, the third driving unit can drive the cutting tool to move close to or away from a wire to be cut; and the limiting portion limits the distance by which the cutting tool moves close to said wire. The bond head assembly can provide a foundation for improving the wire cutting precision and the wire cutting quality of the bonding machine.

Description

Welding head assembly, bonding machine and bonding method Technical Field

[0001] The present invention relates to the field of bonding technology, and in particular to a welding head assembly, a bonding machine and a bonding method. Background Art

[0002] Wire bonding is a method of using thin metal wires to weld metal wires to substrates using heat, pressure, and ultrasound to achieve electrical connection between the chip and the substrate.

[0003] The bonding head assembly in a bonding machine is the working component that performs the bonding process. It typically includes a wedge and a cutter. The wedge has a wire channel inside. The wire used for welding is guided through the channel. The free end of the wedge uses heat, pressure, and ultrasonic vibrations to weld the wire to the substrate, completing the bonding process. The cutter then cuts the wire after the bonding process is complete.

[0004] In existing wedge bonders, the primary tangent method is passive tangent, where overpressure on the splitting blade causes another blade to cut the wire. The entire tangent process is powered by the Z-axis motion of the bond head assembly. The control accuracy of the tangent depth depends on feedback from the Z-axis scale installed on the bond head. However, due to the large Z-axis travel and load, the corresponding high inertia motion generates significant vibration, making it difficult to achieve high-precision control of the tangent depth with passive tangent. Improving the tangent accuracy and quality of bonders is a pressing issue.

[0005] Summary of the Invention

[0006] The object of the present invention is to provide a welding head assembly, which can provide a basis for improving the tangent accuracy and tangent quality in a bonding machine.

[0007] To achieve the above-mentioned purpose, the welding head assembly includes:

[0008] Fixed frame;

[0009] a first driving unit, fixedly connected to the fixing frame;

[0010] a welding head frame, drivingly connected to the first driving unit, and capable of changing the distance between the welding head frame and the fixing frame when the first driving unit is actuated;

[0011] A second driving unit, fixedly connected to the welding head frame;

[0012] a wedge, in transmission connection with the second drive unit, capable of driving the wedge to extend or retract from the welding head frame to approach or move away from the part to be welded when the second drive unit is actuated;

[0013] a third driving unit, fixedly connected to the welding head frame;

[0014] a cutter, drivingly connected to the third drive unit;

[0015] a first detection component, configured to detect the relative displacement between the welding head frame and the fixing frame; and

[0016] A second detection component is used to detect the relative displacement between the wedge and the welding head frame;

[0017] Among them, the third driving unit is a solenoid, and a limiting part is provided on the welding head frame. When the third driving unit is actuated, it can drive the cutter to move toward or away from the wire to be cut, and the limiting part limits the movement distance of the cutter toward the direction of the wire to be cut.

[0018] In one or more embodiments, the first driving unit is a cylindrical linear motor, and the second driving unit is a voice coil motor.

[0019] In one or more embodiments, the first detection unit is a first grating scale assembly, including a first reading head and a first grating scale, the first reading head is arranged on the fixed frame, and the first grating scale is fixedly connected to the welding head frame.

[0020] In one or more embodiments, the second detection unit is a second grating scale assembly, including a second reading head and a second grating scale, the second reading head is arranged on the welding head frame, and the second grating scale is fixedly connected to the splitting knife.

[0021] In one or more embodiments, the wedge is supported in the welding head frame by an elastic member.

[0022] In one or more embodiments, the welding head frame and the first driving unit are connected via a lifting rod.

[0023] On the other hand, according to some embodiments of the present application, a bonding machine is provided, which includes the welding head assembly as described above, and the welding head assembly is fixedly connected to the bonding machine through the fixing frame.

[0024] On the other hand, according to some embodiments of the present application, a bonding method is provided, which uses a bonding machine having the aforementioned bonding head assembly for bonding, and the bonding method includes the following steps:

[0025] a. activating the first drive unit to lower the welding head frame as a whole to a first distance;

[0026] b. activating the second drive unit to lower the cleaver by a second distance and bonding the wire drawn from the cleaver's lead channel to the substrate;

[0027] c. After bonding is completed, the third drive unit is activated to lower the cutter by a third distance to cut the bonded wire;

[0028] d. Determine whether the cutter in step c completely cuts the wire. If not, record the wire diameter of the uncut portion as the fourth distance;

[0029] e. Adjust the bonding parameters so that during the next bonding process:

[0030] When the first driving unit is actuated, the welding head frame is lowered as a whole by a first adjustment distance, where the first adjustment distance is the sum of the first distance and the fourth distance;

[0031] When the second driving unit is activated, the riving knife is lowered by a second adjustment distance, where the second adjustment distance is obtained by subtracting the fourth distance from the second distance.

[0032] On the other hand, according to some embodiments of the present application, a bonding method is provided, which uses a bonding machine having the aforementioned bonding head assembly for bonding, and the bonding method includes the following steps:

[0033] When it is necessary to increase the cutting depth of the wire by the cutter, the increased cutting depth is defined as a first depth, and the bonding parameters are adjusted so that when the first driving unit is actuated, the overall lowering distance of the welding head frame increases by the first depth, and when the second driving unit is actuated, the lowering distance of the wrecking knife decreases by the first depth;

[0034] When it is necessary to reduce the cutting depth of the wire by the cutter, the increased cutting depth is defined as the second depth, and the bonding parameters are adjusted so that when the first driving unit is actuated, the distance that the welding head frame as a whole descends is reduced by the second depth, and when the second driving unit is actuated, the distance that the splitting knife descends is increased by the second depth.

[0035] The beneficial effects of the present invention are:

[0036] 1) To control the cutter's displacement within a confined space, the welding head assembly employs a solenoid as the third drive unit, and a position limiter is provided on the welding head frame. The solenoid utilizes magnetic attraction or repulsion to drive the cutter's displacement within the confined space. This allows for active tangent control and improved precision without increasing the size of the welding head assembly.

[0037] 2) By configuring a limiter, the third distance the cutter is driven to move remains constant. When the cutter type is changed or the cutter wears out and the actual cutting distance needs to be changed, the overall lowering distance of the welding head frame is adjusted, and this adjustment value is fed back to the lowering distance of the wedge cutter, so that the lowering distance of the wedge cutter is adjusted accordingly. This allows the cutter's tangent depth to be changed while ensuring the wedge cutter's bonding position and process are not affected, thereby ensuring the stability of the cutter quality. At the same time, the entire process only requires adjusting parameters in the software, which is quick and easy to operate and facilitates rapid adjustment of the tangent depth. The tangent depth can be quickly adjusted after changing the cutter through programming and other methods.

[0038] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0040] FIG1 is a perspective schematic diagram of a welding head assembly according to some embodiments of the present application at a first viewing angle;

[0041] FIG2 shows a perspective schematic diagram of a welding head assembly according to some embodiments of the present application at a second viewing angle;

[0042] FIG3 shows a front view of a welding head assembly according to some embodiments of the present application;

[0043] FIG4 shows a partial enlarged schematic diagram of portion A of FIG2 ;

[0044] 5A to 5C are schematic diagrams showing a process according to an embodiment of the present bonding method. DETAILED DESCRIPTION

[0045] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0047] In order to solve the problems of tangent accuracy and tangent consistency of the welding head assembly in the existing bonding machine, an active tangent method is proposed to solve the problem, that is, an independent drive unit is used to drive the actuation of the cutter, so that the cutter can actively tangent independently of the splitting knife. However, in order to improve the accuracy of the control unit for driving the cutter, it is necessary to make the drive unit of the cutter adopt a drive source that can achieve precise subdivision and at the same time be able to control its tangent depth according to the feedback value of the cutter's tangent. Generally, such high-precision, high-force and high-response drive sources are relatively large in size. Using such a drive source will make the overall volume of the welding head assembly very large. In some cases, the space of the welding head assembly does not allow the addition of a drive component with such a configuration, making it difficult to achieve active tangent for the cutter.

[0048] In order to solve the above problems, on the one hand, according to some embodiments of the present application, a welding head assembly is provided. Figure 1 shows a perspective schematic diagram of a welding head assembly according to some embodiments of the present application from a first perspective, Figure 2 shows a perspective schematic diagram of a welding head assembly according to some embodiments of the present application from a second perspective, Figure 3 shows a front schematic diagram of a welding head assembly according to some embodiments of the present application, and Figure 4 shows a partial enlarged schematic diagram of section A of Figure 2.

[0049] The welding head assembly includes a fixed frame 1, a first drive unit 21, a second drive unit 22, a third drive unit 23, a welding head frame 3, a splitter 4, a cutter 5, a first detection assembly, and a second detection assembly. The first drive unit 21 is fixedly connected to the fixed frame 1, and the welding head frame 3 is in transmission connection with the first drive unit 21. When the first drive unit 21 is actuated, it can change the distance between the welding head frame 3 and the fixed frame 1. Therefore, when the welding head assembly is located at the welding station, the actuation of the first drive unit 21 can drive the welding head frame 3 as a whole to move toward or away from the part to be welded.

[0050] The second drive unit 22 is fixedly connected to the welding head frame 3, and the riving knife 4 is in transmission connection with the second drive unit 22. When the second drive unit 22 is actuated, it can drive the riving knife 4 to extend or retract from the welding head frame 3, moving it closer to or further away from the part to be welded. The third drive unit 23 is fixedly connected to the welding head frame 3, and the cutting knife 5 is in transmission connection with the third drive unit 23.

[0051] In order to ensure the stability of the bonding head during the wire bonding process, a detection component is also provided in the welding head assembly, including a first detection component for detecting the relative displacement of the welding head frame 3 and the fixing frame 1, and a second detection component for detecting the relative displacement of the splitting knife 4 and the welding head frame 3, so as to control the displacement distance of the splitting knife 4 during the overall bonding process.

[0052] In order to achieve control over the displacement of the cutter 5 within a confined space, in this welding head assembly, the third drive unit 23 is configured as a solenoid, and a limiter 30 is provided on the welding head frame 3. The solenoid can achieve displacement of the cutter 5 within a confined space by utilizing the characteristics of magnetic attraction or repulsion. When the third drive unit 23 is actuated, it can drive the cutter 5 to move toward or away from the wire to be cut, and the limiter 30 limits the movement distance of the cutter 5 toward the wire 90 to be cut. For example, by configuring solenoids on the welding head frame 3 and the cutter 5 respectively, when the cutter 5 needs to move toward the wire to cut, the two solenoids are caused to repel each other to achieve actuation, and the limiter 30 hard limits the displacement distance of the cutter 5. When the cutter 5 needs to be retracted to the solenoid, the two electromagnets are caused to attract each other to achieve this.

[0053] On the other hand, according to some embodiments of the present application, a bonding machine is also provided, including a welding head assembly as described in one or more embodiments of the present application, and the welding head assembly is fixedly connected to the bonding machine through a fixing frame 1.

[0054] By using the welding head assembly with the above-mentioned configuration, active tangent can be achieved without increasing the volume of the welding head assembly, thereby increasing the accuracy of tangent.

[0055] However, since the electromagnet itself does not have the ability to feedback adjust, when the cutter 5 is worn out after a long period of use or the type of cutter 5 is changed, how to ensure the stability of the tangent quality is another problem to be solved by this application.

[0056] On the other hand, according to some embodiments of the present application, a bonding method is further provided, which uses a bonding machine having a bonding head assembly described in one or more embodiments of the present application for bonding. Figures 5A to 5C are schematic diagrams of a process according to one embodiment of the bonding method. The bonding method includes the following steps:

[0057] Step a: As shown in FIG. 5A to FIG. 5B , the first driving unit 21 is activated to lower the welding head frame 3 as a whole by a first distance x1;

[0058] Step b: As shown in FIG. 5B and FIG. 5C , the second driving unit 22 is activated to lower the cleaver 4 by a second distance x2 , and the cleaver 4 bonds the wires led out of the wire channel of the cleaver 4 to the substrate 91 .

[0059] Step c: As shown in FIG5B and FIG5C , after bonding is completed, the third driving unit 23 is activated to lower the cutter 5 by a third distance x3 to cut the bonded wire.

[0060] Step d: Determine whether the cutter in step c has completely cut the wire. If the wire is not cut as shown in FIG5C , record the wire diameter of the uncut portion as the fourth distance x4.

[0061] Step e. Adjust the bonding parameters so that during the next bonding process:

[0062] When the first driving unit 21 is activated, the welding head frame 3 is lowered as a whole by a first adjustment distance t1. The first adjustment distance t1 is x1+x4.

[0063] When the second driving unit 22 is activated, the riving knife 4 is lowered by a second adjustment distance t2 , and the second adjustment distance t2 is x2 −x4 .

[0064] In existing active tangent equipment, when the tangent depth needs to be changed, the cutter mechanical position needs to be manually adjusted, which is time-consuming and labor-intensive. This is undoubtedly very disadvantageous for the general equipment needs of small batches, multiple varieties, and frequent product switching proposed in the current market. At the same time, there is no feedback on the tangent depth value. The wear of the cutter and the fluctuation of the drive itself have a great impact on the tangent depth, and the stability of the equipment cannot be guaranteed.

[0065] In the present application, by configuring a limiter 30, the third distance x3 of the cutter 5 driven to move is always a constant value. When the type of cutter 5 is changed or the cutter 5 is worn and the actual cutting distance of the cutter 5 needs to be changed, the overall lowering distance of the welding head frame 3 is adjusted, and this adjustment value is fed back to the lowering distance of the wedge 4. This allows the cutting depth of the cutter 5 to be changed while ensuring that the bonding position and process of the wedge 4 are not affected, thereby ensuring the stability of the cutting quality. At the same time, the entire process is fast, facilitating rapid adjustment of the cutting depth. The cutting depth adjustment after the cutter is quickly changed can be achieved through programming or other methods.

[0066] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0067] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0068] In some embodiments of the present welding head assembly, the first drive unit 21 is a cylindrical linear motor, and the second drive unit 22 is a voice coil motor. This configuration enables the first drive unit 21 to achieve fast-response linear displacement, and the second drive unit 22 to stably and accurately control the pressure required for the linear displacement.

[0069] In some embodiments of the present welding head assembly, the first detection unit is a first grating scale assembly, including a first read-write head 61 and a first grating scale. The first read-write head 61 is arranged on a fixed frame 1, and the first grating scale is fixedly connected to the welding head frame 3. The relative position relationship with the first grating scale is obtained by the first read-write head 61, so that the overall position of the welding head frame 3 can be judged, with good motion precision control.

[0070] In some embodiments of the welding head assembly, the second detection unit is a second optical scale assembly, comprising a second read / write head 62 and a second optical scale. The second read / write head 62 is mounted on the welding head frame 3, and the second optical scale is fixedly connected to the wedge 4. The second read / write head 62 can obtain a relative position relationship with the second optical scale, thereby determining the overall position of the wedge 4 and achieving good motion precision control.

[0071] In some embodiments of the present welding head assembly, the splitting knife 4 is supported in the welding head frame 3 by an elastic member, which can be, for example, a coil spring, so that when the second driving unit 22 drives the splitting knife 4, the displacement of the splitting knife 4 will not generate excessive friction between the welding head frame 3.

[0072] In some embodiments of the welding head assembly, the welding head frame 3 and the first driving unit 21 are connected via a lifting rod 7 .

[0073] In another aspect, according to some embodiments of the present application, a bonding method is further provided, wherein bonding is performed using a bonding machine having a bonding head assembly described in one or more embodiments of the present application, and the bonding method comprises the following steps:

[0074] When the cutting depth of the cutter on the wire needs to be increased, the increased cutting depth is defined as the first depth, and the bonding parameters are adjusted so that when the first driving unit 21 is actuated, the overall descending distance of the welding head frame 3 increases by the first depth, and when the second driving unit 22 is actuated, the descending distance of the wrecking knife 4 decreases by the first depth;

[0075] When it is necessary to reduce the cutting depth of the wire by the cutter, the increased cutting depth is defined as the second depth, and the bonding parameters are adjusted so that when the first driving unit 21 is actuated, the overall descending distance of the welding head frame 3 is reduced by the second depth, and when the second driving unit 22 is actuated, the descending distance of the splitting knife 4 is increased by the second depth.

[0076] Through the above method, the cutting depth can be quickly adjusted, thereby improving the adaptability to different cutting requirements.

[0077] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A welding head assembly, characterized in that, Comprising: A fixing frame; A first driving unit fixedly connected to the fixing frame; A welding head frame drivingly connected to the first driving unit, and when the first driving unit actuates, the distance between the welding head frame and the fixing frame can be changed; A second driving unit fixedly connected to the welding head frame; A bonding tool drivingly connected to the second driving unit, and when the second driving unit actuates, the bonding tool can be driven to extend or retract from the welding head frame to approach or move away from the component to be welded; A third driving unit fixedly connected to the welding head frame; A cutting tool drivingly connected to the third driving unit; A first detection assembly for detecting the relative displacement between the welding head frame and the fixing frame; And A second detection assembly for detecting the relative displacement between the bonding tool and the welding head frame; Wherein, the third driving unit is a solenoid, and a limiting portion is provided on the welding head frame. When the third driving unit actuates, the cutting tool can be driven to move in a direction approaching or moving away from the wire to be cut, and the limiting portion limits the moving distance of the cutting tool in the direction approaching the wire to be cut.

2. The soldering head assembly according to claim 1, wherein The first driving unit is a cylindrical linear motor, and the second driving unit is a voice coil motor.

3. The soldering head assembly according to claim 1, wherein The first detection unit is a first grating scale assembly, including a first reading head and a first grating scale. The first reading head is arranged on the fixing frame, and the first grating scale is fixedly connected to the welding head frame.

4. The soldering head assembly according to claim 1, characterized in that The second detection unit is a second grating scale assembly, including a second reading head and a second grating scale. The second reading head is arranged on the welding head frame, and the second grating scale is fixedly connected to the bonding tool.

5. The soldering head assembly according to claim 1, characterized in that, The bonding tool is supported in the welding head frame by an elastic member.

6. The soldering head assembly according to claim 1, wherein The welding head frame and the first driving unit are connected by a lifting rod.

7. A wire bonder, characterized in that, Comprising the welding head assembly according to any one of claims 1 to 6, and the welding head assembly is fixedly connected to the bonding machine through the fixing frame.

8. A bonding method, characterized in that, Using a bonding machine having the welding head assembly according to any one of claims 1 to 6 for bonding, the bonding method comprising the following steps: a. Actuate the first driving unit to lower the entire welding head frame by a first distance; b. Actuate the second driving unit to lower the bonding tool by a second distance, and cause the bonding tool to bond the wire led out from the lead channel of the bonding tool and the substrate; c. After bonding is completed, actuate the third driving unit to lower the cutting tool by a third distance to cut the wire after bonding is completed; d. Determine whether the cutting tool completely cuts the wire in step c. If not, record the wire diameter of the uncut part as a fourth distance; e. Adjust the bonding parameters so that in the next bonding process: When the first driving unit actuates, lower the entire welding head frame by a first adjustment distance, and the first adjustment distance is the sum of the first distance and the fourth distance; When the second driving unit actuates, lower the bonding tool by a second adjustment distance, and the second adjustment distance is obtained by subtracting the fourth distance from the second distance.

9. A bonding method, characterized in that, Using a bonding machine having the welding head assembly according to any one of claims 1 to 6 for bonding, the bonding method comprising the following steps: When it is necessary to increase the cutting depth of the cutting tool on the wire, define the increased cutting depth as the first depth, and adjust the bonding parameters so that when the first driving unit actuates, the overall descending distance of the bonding head frame increases by the first depth, and when the second driving unit actuates, the descending distance of the splitting tool decreases by the first depth; distance decreases by the first depth; When it is necessary to decrease the cutting depth of the cutting tool on the wire, define the increased cutting depth as the second depth, and adjust the bonding parameters so that when the first driving unit actuates, the overall descending distance of the bonding head frame decreases by the second depth, and when the second driving unit actuates, the descending distance of the splitting tool increases by the second depth.

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